In addition, there is a perception that Singapore society is highly regulated through the criminalization of many activities which are considered as fairly harmless in other countries. These include failing to flush toilets after use,[6]littering,[7]jaywalking,[8] the possession of pornography,[9] the sale of chewing gum,[10] and sexual activity; such as oral and anal sex between men.[11] It has been claimed that one of the results of such heavy regulation is that Singapore has one of the lowest incidences of violent crimes in the world.[12] A catchphrase recently used in a police anti-crime campaign was "Low crime does not mean no crime".

For most of the 19th century the criminal law which applied in the Straits Settlements (comprising Prince of Wales' Island (Penang), Singapore and Malacca) was that of the United Kingdom, insofar as local circumstances permitted. There was little doubt that at the time English common law crimes were recognized in these territories. However, due to problems such as doubts as to the applicability of Indian Acts, in 1871 the Straits Settlements Penal Code 1871[15] was enacted. It came into operation on 16 September 1872. The Code was practically a re-enactment of the Indian Penal Code.

Over the years, the Penal Code has been amended several times. In 1973 punishments for certain offences were enhanced, and by the Penal Code (Amendment) Act 1984,[citation needed] which came into effect on 31 August 1984, mandatory minimum penalties were introduced for certain offences. A major review of the Code was launched in 2006.

Prior to 1870 the law relating to criminal procedure in force in Singapore was found mainly in the Indian Criminal Procedure Act 1852,[16] which was applicable because the Supreme Government of India had power to legislate for the Straits Settlements. After the passing of the Penal Code in 1871, the Indian Act was replaced by the Criminal Procedure Ordinance.[17] However, in general it continued to apply the English system of criminal procedure to the Penal Code. This was subsequently found to be impracticable as the Penal Code had done away with the division of crimes into felonies and misdemeanours. Accordingly, the Criminal Procedure Ordinance 1873[18] was passed to remedy the situation. The Ordinance also did away with the procedure for indictments in favour of charges for all criminal offences; and abolished the grand jury, and special and common juries.

A new Code of Criminal Procedure was enacted in 1902.[citation needed] The present Criminal Procedure Code[19] was passed by the Legislative Council of the Colony of Singapore on 28 January 1955. All criminal offences under the Penal Code or other statutes are inquired into and tried according to the Criminal Procedure Code.

The Penal Code defines the elements of each offence and prescribes the maximum, and occasionally also the minimum, penalties for it. The basic form of an offence (commonly referred to as the "simple offence" or, using Latin terminology, as the "offence simpliciter") has the lowest penalties. More serious forms of the offence are defined as separate offences and attract stiffer penalties.

For instance, theft is defined in section 378 of the Code, and section 379 makes simple theft (or theft simpliciter) an offence punishable with imprisonment of up to three years or with fine or both. Section 379A punishes the theft of a motor vehicle or any component part of a motor vehicle with imprisonment of not less than one year and not more than seven years and a fine. Sections 380 and 381 respectively make it offences to commit theft in any building, tent or vessel which is used as a human dwelling or for the custody of property; and, while being a clerk or servant, or being employed in the capacity of a clerk or servant, to commit theft of any property in the possession of one's master or employer. In both cases the penalty is imprisonment of up to seven years and a fine. The most serious theft offence is that of committing theft, having made preparation for causing death or hurt or restraint, or fear of death or of hurt or of restraint, to any person in order to commit the theft, or in order to effect an escape after committing the theft, or in order to retain property taken by the theft. The maximum penalty is imprisonment for up to ten years and caning with not less than three strokes.

An offender is usually charged with the most serious offences that can be established on the facts of the case. On representations being made by the offender's lawyer to the prosecuting authority, the Prosecution may agree to charge the offender with lesser offences provided that he or she agrees to plead guilty to the reduced charges.

Narcotics laws established by the Misuse of Drugs Act are very strict. Anyone caught with more than 15 grams (0.53 oz) of heroin (diamorphine), 30 grams (1.1 oz) of cocaine or morphine, 250 grams (8.8 oz) of methamphetamine, or 500 grams (18 oz) of cannabis faces mandatory capital punishment, as they are deemed to be trafficking in these substances.[20] The stated quantities are the net weight of the substances after they have been isolated by laboratory analysis. Between 1991 and 2004, 400 people were hanged in Singapore, mostly for drug trafficking, one of the highest per-capita execution rates in the world.[13] Persons caught with amounts of controlled substances less than the quantities that would warrant the mandatory death sentence may be spared from the gallows. They may, however, still face harsh penalties ranging from long terms of imprisonment to a maximum of 24 strokes of the cane (for males).